[R] How to convert factors to numbers

[chuck.01]

Using your posed data, the variable price was numeric:

data.precios <-
read.table("http://r.789695.n4.nabble.com/file/n4498828/p_diarios.txt",
header=T)

str(data.precios)
'data.frame':	1996 obs. of  2 variables:
 $ time : int  37988 37991 37993 37994 37995 37998 37999 38000 38001 38002
...
 $ price: num  18.1 26.1 30.9 34.7 27.6 ...


HOWEVER!
If I follow your code (eg. using " read.table(... , dec=",", sep="\t")":

 data.precios <-
read.table("http://r.789695.n4.nabble.com/file/n4498828/p_diarios.txt", 
header =TRUE , dec=",", sep="\t")
> str(data.precios)
'data.frame':	1996 obs. of  2 variables:
 $ time : int  37988 37991 37993 37994 37995 37998 37999 38000 38001 38002
...
 $ price: Factor w/ 1639 levels "10.80","12.53",..: 12 126 213 342 160 186
219 37 54 69 ...

It is a factor.... but I can change it like this:

> Price <- as.numeric(data.precios$price) 
> str(lPrice)
 num [1:1996] 12 126 213 342 160 186 219 37 54 69 ...


I think avoiding it ever becoming a factor would be the better path. 
Good luck. 





sandro wrote
> 
> Hello, I am relatively new to using R.
> 
> The text file contains the date and price .  I want to read and manipulate
> the data in R.  However, when I use read.table, it treats all of the data
> as "factors" and I do not know how to treat the data as numbers:
> 
>  http://r.789695.n4.nabble.com/file/n4498828/p_diarios.txt p_diarios.txt 
> 
> setwd ("C:\\Users\\Sandro\\Dropbox\\R")
> data.precios <- read.table ("p_diarios.txt ", header =TRUE
> , dec=",", sep="\t")
> Time <- data.precios$time # 01.02.2004 - 12.05.2011
> Price <- data.precios$price # Historical spot price
> log.Price <- log(data.precios$price)
> Error en Math.factor(c(12L, 126L, 213L, 342L, 160L, 186L, 219L, 37L, 54L, 
> : 
>   log not meaningful for factors
> 
> As you can see, I cannot calculate the price logarithms.
> 
> Any help is appreciated.
> 
> Sandro
> 


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